RETINAL-PIGMENT EPITHELIUM-CELLS CULTURED ON SYNTHETIC BIODEGRADABLE POLYMERS

Alterations in the normal structure or functions of retinal pigment ep ithelium (RPE) can result in a number of ocular diseases. Implantation of RPE cells cultured on thin, biodegradable polymer films may provid e a means of transplant ing an organized sheet of RPE cells with disti nct apical/basal characteristics for the restoration of normal RPE fun ction. We have investigated the interactions of human RPE cells with d ifferent biodegradable polymer films to assess their suitability as su bstrates for RPE culture. Four biodegradable polymers were used: low m olecular weight (MW) 50:50 poly(DL-lactic-co-glycolic acid) (PLGA); hi gh MW 50:50 PLGA; 75:25 PLGA; and poly(L-lactic acid) (PLLA). Polymer film substrates were manufactured using a solvent casting technique. H uman fetal RPE cells (10-16 weeks gestational) were plated on the poly mer substrates and the cultures assessed with respect to cell attachme nt and proliferation. Histological and immunohistochemical studies wer e performed on the cells after 8 days in culture. RPE cells attached t o all the polymers studied after 8 h in culture. After 8 h, 80.2 +/- 9 .5% and 82.3 +/- 7.9% of the plated cells were attached to substrates of high MW 50:50 PLGA and 75:25 PLGA, respectively. The cells prolifer ated on all substrates, and there was about a threefold increase in ce ll number over the 8-day culture period on all the polymers studied. I mmunohistochemistry after 8 days in culture demonstrated RPE cells lab eled with a distinct reaction product for cytokeratin in the cell cyto plasm. All the polymers studied were suitable for RPE culture; however , high MW 50:50 PLGA and 75:25 PLGA proved to be the best in terms of manufacturing properties, cell attachment, and proliferation. These po lymers can provide a suitable substrate for RPE cell culture and hold promise for the subretinal implantation of organized sheets of RPE cel ls. (C) 1997 John Wiley & Sons, Inc.